package main

import (
"fmt"
"time"
)

func say(s string) {
	for i := 0; i < 5; i++ {
		time.Sleep(200 * time.Millisecond)
		fmt.Println(s)
	}
}

func main() {

	begin := time.Now()
	go say("hello")	// 去掉 go 试试，看看耗时多少
	say("world")

	end := time.Now()

	fmt.Println("耗时：", end.Sub(begin))

}
